Carrier Screening: I’ve had it done before. Why do it again?

May 26, 2020

genetic testing_carrier screening

Planning a pregnancy? Carrier screening can be completed before pregnancy or during pregnancy and can provide you with information that can be helpful to plan your next steps. Whether it’s the first time you have completed carrier screening or whether it’s updated carrier screening, here are a few things to think about.

What is carrier screening?

Not all carrier screening is the same. Some conditions are more common and some are rarer. Some laboratories have large panels (or collections) of genes that provides information for many different conditions. Some laboratories have smaller panels of just a few more common conditions. Speaking with a genetic counselor allows you to determine what type of carrier screening is the best fit for you and the information you would like to learn before or during pregnancy.

People typically have two copies of every gene in their body. A person is referred to as a carrier if they have a genetic change in one copy of a gene that is associated with a genetic condition. It is incredibly common to be a carrier for one or multiple genetic conditions! Carrier screening for specific genetic conditions is an important part of screening during pregnancy, but many people receive screening even before pregnancy as this helps with family planning. 

Carrier screening is genetic testing that uses a person’s blood or saliva to detect whether there is a genetic change in selected genes that they carry. Most often individuals do not have a family history of these conditions. Further, most carriers do not have symptoms of a genetic condition at all. If both parents are carriers for the same condition, then there is a 1 in 4 or 25% chance a pregnancy could have this condition. 

Should I have updated carrier screening?

I have done carrier screening before…why do it again? My genes don’t change right? 

Those are good questions! If you have completed carrier screening before then you have already gained some information regarding whether you are a carrier or not. However, carrier screening through different laboratories are not all the same. Newer tests provide a risk assessment that is actually better than older testing because they look at the genes in more detail. Also, sometimes you can be tested for even more conditions than you previously completed. So you’re right! Our genes do not change over time, but our testing does! 

Updated carrier screening is helpful for prospective parents who want to know the chances of having a child with a genetic condition. 

To complete carrier screening or not?

Meeting with a genetic counselor to discuss family history of a genetic condition or even just the population chance to be a carrier for conditions is helpful before and during pregnancy. Ask to speak to a genetic counselor if you have questions regarding your carrier screening that was already completed or if you would like to complete carrier screening for the first time!